<template>
  <div class="type-nav">
    <div class="container">
      <div @mouseleave="leaveIndex">
        <h2 class="all" @mouseenter="goshow">全部商品分类</h2>
        <!-- 三级联动 -->
        <transition name="sort">
          <div class="sort" v-show="show">
            <!-- //!!利用事件委派+编程式导航进行数据传参以及路由的跳转 -->
            <div class="all-sort-list2" @click="gosearch" v-show="show">
              <div
                :class="{ cur: currentIndex == index }"
                class="item bo"
                v-for="(c1, index) in categoryLists.slice(0, 15)"
                :key="c1.categoryId"
              >
                <h3 @mouseenter="changeIndex(index)">
                  <a
                    :data-categoryName="c1.categoryName"
                    :data-category1id="c1.categoryId"
                    >{{ c1.categoryName }}</a
                  >
                  <!-- //!!视频026里面讲解了为什么这里不用声明式导航来跳转 -->
                  <!-- <router-link to="/search">{{ c1.categoryName }}</router-link> -->
                </h3>
                <!--  此处也可以用v-show来替代 :style="{ display: currentIndex == index ? 'block' : 'none' }" -->
                <!-- 二级，三级分类 -->
                <div
                  class="item-list clearfix"
                  :style="{ display: currentIndex == index ? 'block' : 'none' }"
                >
                  <div
                    class="subitem"
                    v-for="c2 in c1.categoryChild"
                    :key="c2.categoryId"
                  >
                    <dl class="fore">
                      <dt>
                        <a
                          :data-categoryName="c2.categoryName"
                          :data-category2id="c2.categoryId"
                          >{{ c2.categoryName }}</a
                        >
                      </dt>
                      <dd>
                        <em v-for="c3 in c2.categoryChild" :key="c3.categoryId">
                          <a
                            :data-categoryName="c3.categoryName"
                            :data-category3id="c3.categoryId"
                            >{{ c3.categoryName }}</a
                          >
                        </em>
                      </dd>
                    </dl>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </transition>
      </div>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>

<script>
import { mapActions, mapState } from "vuex";
//按需引入节流函数，其他的函数没有引入（模块），这样做的好处是，当你打包项目的时候体积会更小一些
import throttle from "lodash/throttle";
export default {
  name: "TypeNav",
  data() {
    return {
      currentIndex: -1,
      show: true,
    };
  },
  methods: {
    //这里的发送请求 在app.vue里面执行了 所以进行里注释掉
    //向服务器发送请求
    // ...mapActions("home", ["categoryList"]),
    //鼠标进入 修改数据 并进行节流操作
    //!!!引入节流函数
    changeIndex: throttle(function (index) {
      this.currentIndex = index;
    }, 100),
    //鼠标离开  恢复原样
    leaveIndex() {
      this.currentIndex = -1;
      //在search组件里面 在全部商品分类里 离开鼠标 隐藏
      if (this.$route.name == "search") {
        this.show = false;
      }  else if(this.$route.name == "detail"){
         this.show = false;
      }
    },
    //当鼠标移动到全部商品分类 显示
    goshow() {
      this.show = true;
    },
    //!!性能优化  的获得数据 向路由跳转和传参
    //!!e.target可以拿到上面的html自定义的属性名和属性值 (用了事件委派)
    gosearch(e) {
      let element = e.target;
      /*  console.log(e);
      console.log(element); */
      // 进行数据解构
      let { categoryname, category1id, category2id, category3id } =
        element.dataset;
      if (categoryname) {
        let location = { name: "search" };
        let query = { categoryName: categoryname };
        if (category1id) {
          query.category1Id = category1id;
        } else if (category2id) {
          query.category2Id = category2id;
        } else {
          query.category3Id = category3id;
        }
        location.query = query;
        //和搜索的keyword参数一起传   看Hearder组件
        location.params = this.$route.params;
        this.$router.push(location);
      }
    }
    
  },
  mounted() {
    // mounted这里面不能写 ...mapActions("home", ["categoryList"]), 这种格式的。
    //这里的发送请求 在app.vue里面执行了 所以进行里注释掉
    // this.$store.dispatch("home/categoryList");
    // this.categoryList();
    //!!在search里面隐藏三级联动
    if (this.$route.name == "search") {
      this.show = false;
    } else if (this.$route.name == "detail") {
      this.show = false;
    }
  },
  computed: {
    //拿到数据使用
    ...mapState("home", ["categoryLists"]),
    //第二种写法
    /*   ...mapState({
      categoryLists: (state) => {
        return state.home.categoryLists;
      },
    }), */
  },
};
</script>

<style scoped lang="less">
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      height: 461px;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        .item {
          h3 {
            line-height: 30px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;
            // height: 450px;
            // overflow: hidden;

            a {
              color: #333;
            }
          }

          .item-list {
            // display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                  }
                }
              }
            }
          }
          /* 
          &:hover {
            .item-list {
              display: block;
            }
          } */
        }
        .cur {
          background: skyblue;
        }
      }
    }
    //!!添加过渡动画
    .sort-enter,
    .sort-leave-to {
      height: 0px;
    }
    .sort-enter-to,
    .sort-leave {
      height: 461px;
    }
    .sort-enter-active,
    .sort-leave-active {
      transition: all 0.2s linear;
    }
  }
}
</style>